Field of the Invention
The present invention relates to an image forming apparatus equipped with a sleep function and for forming an image using an image forming unit, and to a control method thereof.
Description of the Related Art
Multi-function peripherals equipped with functions such as a copy function, a print function, a FAX function and a network function are known. Starting up such a multi-function peripheral begins with activation processing in response to the device being powered on, and subsequently the device starts up in a normal mode and enters a standby state. In general, a copy operation and a print operation are performed in the standby state. In order to perform power saving control, multi-function peripherals are further equipped with a sleep mode that consumes less power than in the standby state.
Multi-function peripherals (image forming apparatuses) include a controller unit for executing various function and performing power controls and an engine unit for executing output control, and are configured so that these units are activated independently. Therefore, return processing from the sleep mode is performed on the basis of data transferred via a network, for example. In this processing, since there is a time difference between a response time to a wake-up instruction from the network and a startup time of the controller unit, activation of the engine unit is started after the startup of the controller unit. As a result, it takes a long time to start up a multi-function peripheral when returning from the sleep mode. To resolve this problem, Japanese Patent Laid-Open No. 2007-43665 proposes initialization processing of an image forming apparatus when a trigger for returning from a power saving mode to the normal mode arises.
In this conventional technique, however, during the initialization processing of the image forming apparatus, a controller of the engine unit for output control determines whether or not the engine unit is to perform the initialization, and therefore it takes time to activate the apparatus.
Additionally, under such circumstances, conventional image forming apparatuses are capable of receiving several types of jobs at a network port, including print processing, inquiries about apparatus information, and storage. These jobs are received at a single port, and the controller unit needs processing time to determine whether or not the received jobs require returning from the sleep state. Therefore, such an image forming apparatus has to start up both the controller unit and the engine unit to return from the sleep state, thus requiring a longer activation time.